According to a Car Advice interview with Lexus IS Chief Engineer Junichi Furuyama, Lexus may be planning to replace the model’s 2.5L V6 with a small turbocharged engine:

Speaking at the Detroit auto show, where the third-generation Lexus IS made its official debut, the chassis chief said that Lexus “still have some time to consider” whether the existing 2.5-litre naturally aspirated V6 would be replaced by a smaller, boosted engine.

“Turbocharged downsizing engine is something that we keep as one of the options,” added Furuyama-san.

“Currently we are considering whether or not we should maintain the current naturally aspirated V6 engine, or we should shift to turbocharged downsizing.”

Furuyama-san is likely referring to four-cylinder 2.0L turbocharged engine that was mentioned in last year’s technical timeline — expected to be introduced in a currently-unidentified vehicle in 2014, this new engine would provide a much needed power boost to the IS lineup.